Some books are made with rigid spines. Others, usually paperback books, are typically manufactured by fastening a stack of pages, known as a book block, to a flexible cardboard or paper cover by gluing one edge of the book block to the spine of the cover with a flexible glue. Although the spines of such books are flexible, such books do not readily lie flat when opened, and therefore are often hard to maintain in a readable position. Attempts by the reader to overcome the tendancy of such books to close or pages to turn, by bending the spines often result in broken spines and a subsequent loss of pages from the book blocks. Books with unflexible spines are even less likely to lie flat when opened.
There are a number of patents which disclose book binding constructions. U.S. Pat. No. 2,523,860, issued Sept. 26, 1950 to Budden, disclosures an adhesive binding for books in which one of two or three adhesive layers which bind the spinal edge of the book block to the book cover has an intermittent pattern. In Budden, the entire surface of the spinal edge of the book block is completely covered with adhesive by either a preliminary adhesive coat or by the combination of the intermittent adhesive pattern and a subsequent adhesive coat (see column 4, lines 6-14, 19-34 and 35-50). In the construction exemplified by the Budden patent, the primary objective of the Applicant's invention, namely making the book lie flat when open, could not be achieved, was much as the Budden patent is directed to saving adhesive, providing greater resistance to shear forces, and decreasing resistance to rounding and backing of the book block with conventional machines.
U.S. Pat. No. 4,299,410, issued Nov. 10, 1981 to Jukola, discloses a soft-covered book binding in which a layer of gauze, cloth or crepe, fastened to the entire spine of the book block, binds the book block together while the soft book cover is fastened to only the first and last pages of the book block (column 1, lines 50-58). Thus, the Jukola patent does not address the primary objective of the present invention, namely making a book lie flat.
Other references that deal with book binding problems do not recognize the problems or the solutions with which the present invention is concerned including U.S. Pat. No. 2,914,318, issued Nov. 24, 1959 to McGarvey; 2,277,265, issued Mar. 24, 1942 to Zahniser; 4,471,976, issued Sept. 18, 1984 to Giulie; 4,371,194, issued Feb. 1, 1983 to Wang; and 3,570,071 issued Mar. 16, 1971 to Wardell.